GIA's Gubelin Gem Project: Corundum

Corundums (ruby and sapphires) occur in all colors of the spectrum, and have remained popular gemstones from ancient times to the present day.
Corundums (ruby and sapphires) occur in all colors of the spectrum, and have remained popular gemstones from ancient times to the present day. Photo by Robert Weldon/GIA

Ruby and sapphire (usually blue, but also in every other color) have been the most important colored gemstones for several thousand years. Originating historically in southeast and central Asia, and more recently in eastern Africa, these colored varieties of the mineral corundum have been much sought as gems because of their rarity, color and durability. Gem corundum can display asterism and chatoyancy due to the presence of oriented mineral inclusions, and in some cases, a change of color when viewed under different light sources.

 
33066
Corundum - Ruby 1.77 ct from Myanmar

1.77 ct Corundum - Ruby
Myanmar (PDF)
 		 33068
Corundum - Ruby 1.62 ct from Nepal

1.62 ct Corundum - Ruby
Nepal (PDF)
 		 33069
2.02 ct Corundum - Ruby from Sri Lanka

2.02 ct Corundum - Ruby
Sri Lanka (PDF)
 
33070
3.05 ct Corundum - Ruby from Sri Lanka

3.05 ct Corundum - Ruby
Sri Lanka (PDF)
 		 35115
2.47 ct Corundum - Ruby from Thailand

2.47 ct Corundum - Ruby
Thailand (PDF)
 		 35103
1.92 ct Corundum - Ruby from Cambodia

1.92 ct Corundum - Sapphire
Cambodia (PDF)
 
34572
2.97 ct corundum-sapphire from Myanmar

2.97 ct Corundum - Sapphire
Myanmar (PDF)
 		 33081
3.46 ct corundum-sapphire from Myanmar

3.46 ct Corundum - Sapphire
Myanmar (PDF)
 		 33085
4.38 ct corundum-sapphire from Myanmar

4.38 ct Corundum - Sapphire
Myanmar (PDF)
 
34575
5.78 ct corundum-sapphire from Myanmar

5.78 ct Corundum - Sapphire
Myanmar (PDF)
 		 33078
6.40 ct corundum-sapphire from Myanmar

6.40 ct Corundum - Sapphire
Myanmar (PDF)
 		 35147
3.89 ct Corundum - Sapphire from Thailand

3.89 Corundum - Sapphire
Thailand (PDF)
 
35146
3.97 ct Corundum - Sapphire from Thailand

3.97 ct Corundum - Sapphire
Thailand (PDF)
 		 34581
6.99 ct corundum-sapphire from Myanmar

6.99 ct Corundum - Sapphire
Myanmar (PDF)
 		 34580
8.29 ct corundum-sapphire from Myanmar

8.29 ct Corundum - Sapphire
Myanmar (PDF)
 
33092
3.48 ct Corundum-Sapphire from Sri Lanka

3.48 ct Corundum - Sapphire
Sri Lanka (PDF)
 		 33074
4.51 ct Corundum-Sapphire from Sri Lanka

4.51 ct Corundum - Sapphire
Sri Lanka (PDF)
 		 33075
6.36 ct Corundum-Sapphire from Sri Lanka

6.36 ct Corundum - Sapphire
Sri Lanka (PDF)
 
33061
7.74 ct Corundum - Sapphire from Sri Lanka

7.74 ct Corundum - Sapphire
Sri Lanka (PDF)
 		 33063
8.70 ct Corundum - Sapphire from Sri Lanka

8.70 ct Corundum - Sapphire
Sri Lanka (PDF)
 		 33079
9.16 ct Corundum - Sapphire from Sri Lanka

9.16 ct Corundum - Sapphire
Sri Lanka (PDF)
 
35144
4.94 ct Corundum - Sapphire from Thailand

4.94 ct Corundum - Sapphire
Thailand (PDF)
 		 35128
5.28 ct Corundum - Sapphire from Thailand

5.28 ct Corundum - Sapphire
Thailand (PDF)
 		 33084
15.87 ct Corundum - Sapphire from Sri Lanka

15.87 ct Corundum - Sapphire
Sri Lanka (PDF)
 
33087
4.29 ct Corundum - Sapphire from Tanzania

4.29 ct Corundum - Sapphire
Tanzania (PDF)
 		 33077
5.06 ct Corundum - Sapphire from Tanzania

5.06 ct Corundum - Sapphire
Tanzania (PDF)
 		 35138
2.2 ct Corundum - Sapphire from Thailand

2.20 ct Corundum - Sapphire
Thailand (PDF)
 
35095
2.72 ct Corundum - Sapphire from Thailand

2.72 ct Corundum - Sapphire
Thailand (PDF)
 		 35111
2.72 ct Corundum - Sapphire from Thailand

2.72 ct Corundum - Sapphire
Thailand (PDF)
 		 33080
2.86 ct Corundum - Sapphire from Thailand

2.86 ct Corundum - Sapphire
Thailand (PDF)
 
35112
3.01 ct Corundum - Sapphire from Thailand

3.01 ct Corundum - Sapphire
Thailand (PDF)
 		 35113
3.39 ct Corundum - Sapphire from Thailand

3.39 ct Corundum - Sapphire
Thailand (PDF)
 		 35110
3.76 ct Corundum - Sapphire from Thailand

3.76 ct Corundum - Sapphire
Thailand (PDF)
 
33091
7.65 ct Corundum - Sapphire from Thailand

7.65 ct Corundum - Sapphire
Thailand (PDF)